Method for manufacturing antenna and method for manufacturing semiconductor device

ABSTRACT

The present invention provides an antenna with low resistance and a semiconductor device having an antenna whose communication distance is improved. A fluid containing conductive particles is applied over an object. After curing the fluid containing the conductive particles, the fluid is irradiated with a laser to form an antenna. As a method for applying the fluid containing the conductive particles, screen printing, spin coating, dipping, or a droplet discharging method is used. Further, a solid laser having a wavelength of 1 nm or more and 380 nm or less is used as the laser.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for manufacturing an antenna.Moreover, the present invention relates to a method for manufacturing asemiconductor device having an antenna.

2. Description of the Related Art

In recent years, development of a semiconductor device which can sendand receive data wirelessly has been actively carried out. Such asemiconductor device is also referred to as an IC tag, an ID tag, an RF(radio frequency) tag, an RFID (radio frequency identification) tag, awireless tag, an electronic tag, a wireless processor, a wirelessmemory, a wireless chip, or the like.

A wireless chip generally includes an antenna and an IC chip. The ICchip is formed using an element layer having a transistor and the likeprovided over a silicon wafer.

As one of characteristics required for an antenna of a wireless chip,there is low resistance of an antenna (a wiring) itself. The Q-value hasbeen generally known as a parameter for evaluating an electriccharacteristic of an antenna, and is represented by a general formula:Q=ωL/R. In the general formula, ωL represents reactance of a coil and Rrepresents electric resistance of the antenna. According to this generalformula, it is apparent that the Q value is inversely proportional toresistance (R) of the antenna, and the Q value is increased as theresistance (R) is reduced. The higher the Q value is, the longer acommunication distance of a wireless chip is. Therefore, there is aconcern that as increasing the resistance (R) of an antenna, the Q valueis reduced, which results in reduction in a communication distance.

As a means for reducing resistance of an antenna, it is desired that aline space (a width between lines) of a wiring used as an antenna isprevented from widening. As a method for forming a wiring used as anantenna, after forming a conductive film, the conductive film issubjected to patterning to form the antenna (for example, see patentdocument 1). Further, in this specification, “patterning” indicatestreatment by which an object is etched into a desired shape.

Patent Document 1: Japanese Patent Application Laid-Open No. 2004-220591

When, after forming a conductive film by sputtering, a method forpatterning the conductive film using a mask made from a resist is used,a line space can be set to be about 10 μm. However, this method hasproblems that since the mask made from a resist is used, the number ofsteps for forming an antenna is increased so that lots of processingtime is required. In addition, manufacturing cost is also increased withincreasing the number of steps and processing time.

In a case of a droplet discharging method using an ink-jet technique,processing time required for forming an antenna is shorter than a caseof using a method using a mask made from a resist; however, a limit of aline space is about 50 μm so that resistance of the antenna isincreased. Note that the droplet discharging method is a method by whicha droplet (also, referred to as a dot) of a composition containing amaterial for a conductive film, an insulating film, or the like isselectively discharged (injected) to form a film in a predeterminedposition, and this method is also referred to as a dot method.

In a case of using screen printing, as compared with a method using amask made from a resist, processing time required for forming an antennais shortened as well as the case of using the droplet dischargingmethod. However, a limit of a line space in the case of using screenprinting is about 50 to 100 μm so that the resistance of the antenna isalso increased. In particular, in a case of forming an antenna using aprinting plate, in which an antenna pattern is formed in advance, theprinting plate must be designed in consideration of the amount of arunning resin. Therefore, it has been necessary to secure enough spacebetween lines of an antenna.

As mentioned above, when processing time required for forming an antennais shortened, a line space of the antenna is increased by theconventional method. Accordingly, a width of an antenna cannot besufficiently widened and resistance of the antenna is increased; andtherefore, it has been difficult to improve a communication distance.Further, in a case of forming a loop antenna as an antenna, thesufficient winding number cannot be secured so that it has beendifficult to manufacture a semiconductor device with a sufficientcommunication distance.

SUMMARY OF THE INVENTION

In view of the above described problems, it is an object of the presentinvention to provide a method for manufacturing an antenna whoseresistance is lower than an antenna formed by a conventionalmanufacturing method by which the antenna is formed without using amask. Further, it is another object of the present invention to providea method for manufacturing a semiconductor device having an antennawhose communication distance is improved as compared with asemiconductor device manufactured by a conventional manufacturingmethod.

One feature of the present invention is that, after a fluid containingconductive particles is applied to a surface of an object (for example,a substrate, a substrate having one surface provided with an insulatingfilm, or an insulating film covering an element such as a thin filmtransistor, which is formed over a substrate) and is cured, the fluidcontaining the conductive particles is irradiated with a laser(subjected to scribing) to form an antenna. Further, a substrate havinga surface with concavity and convexity or a curved surface generated bya thin film transistor, a gate electrode, a wiring, and the like, whichare provided over the substrate, can be used as an object (substrate)over which an antenna is formed, in addition to a substrate having aflat surface.

In an aspect of the present invention regarding a method formanufacturing a semiconductor device, a fluid containing conductiveparticles is applied over a substrate; and after forming a filmcontaining conductive particles by curing the fluid containing theconductive particles, an antenna is formed by irradiating the film witha laser light.

In another aspect of the present invention regarding a method formanufacturing a semiconductor device, a separation layer is formed overa substrate; an element layer having a thin film transistor is formedover the separation layer; a fluid containing conductive particles isapplied to a surface of the element layer; the fluid containing theconductive particles is cured to form a film containing conductiveparticles; and then the film containing the conductive particles isirradiated with a laser light to form an antenna being electricallyconnected to the thin film transistor. Thereafter, a protection layer isformed over the element layer and the antenna; the element layer and theprotection layer are selectively removed to form an opening portion; theelement layer, the antenna, and the protection layer are separated fromthe substrate; and the element layer, the antenna, and the protectionlayer are sealed by using a first flexible film and a second flexiblefilm.

In another aspect of the present invention regarding a method formanufacturing a semiconductor device, a fluid containing conductiveparticles is applied to a surface of a first substrate; the fluidcontaining the conductive particles is cured to form a film containingthe conductive particles; and then the film containing the conductiveparticles is irradiated with a laser light to form an antenna over thefirst substrate. Thereafter, the first substrate over which the antennais formed and a second substrate over which an element layer having athin film transistor is formed over a separation layer are attached toeach other to electrically connect the antenna to the thin filmtransistor; the first and second substrates which are attached to eachother are selectively removed to form an opening portion; the secondsubstrate over which the element layer and the antenna are provided isseparated from the first substrate; and the second substrate over whichthe element layer and the antenna are provided is sealed by using afirst flexible film and a second flexible film.

In another aspect of the present invention regarding a method formanufacturing a semiconductor device, a fluid containing conductiveparticles is applied to a surface of a first substrate; the fluidcontaining the conductive particles is cured to form a film containingthe conductive particles; and then the film containing the conductiveparticles is irradiated with a laser light to form an antenna over thefirst substrate. Thereafter, the first substrate over which the antennais formed and a second substrate over which an element layer having athin film transistor is formed over a separation layer are attached toeach other to electrically connect the antenna to the thin filmtransistor. Then, only the first substrate which is attached to thesecond substrate is ground; the ground first substrate is polished; andthe polished first substrate and the second substrate are sealed byusing a first flexible film and a second flexible film.

In another aspect of the present invention regarding a method formanufacturing a semiconductor device, in the above described structure,screen printing, spin coating, dipping, or a droplet discharging methodis used as a method for applying the fluid containing the conductiveparticles.

Further, in another aspect of the present invention regarding a methodfor manufacturing a semiconductor device, in the above describedstructure, particles mainly containing gold, silver, copper, an alloy ofgold and silver, an alloy of gold and copper, an alloy of silver andcopper, an alloy of gold, silver, and copper, indium tin oxide,conductive oxide in which 2 wt % or more and 20 wt % or less of zincoxide is mixed in indium oxide, conductive oxide in which 2 wt % or moreand 20 wt % or less of silicon oxide is mixed in indium oxide, alead-free solder, or a solder containing lead, are used as theconductive particles.

In another aspect of the present invention regarding a method formanufacturing a semiconductor device, a separation layer is formed overa substrate; an element layer having a thin film transistor is formedover the separation layer; a conductive film is formed over the elementlayer; and then the conductive film is irradiated with a laser to forman anntena being electrically connected to the thin film transistor.Thereafter, a protection layer is formed over the element layer and theantenna; the element layer and the protection layer are selectivelyremoved to form an opening portion; the element layer, the antenna, andthe protection layer are separated from the substrate; and the elementlayer, the antenna, and the protection layer are sealed by using a firstflexible film and a second flexible film.

In another aspect of the present invention regarding a method formanufacturing a semiconductor device, a conductive film is formed over afirst substrate; and then the conductive film is irradiated with a laserto form an antenna over the first substrate. Thereafter, the firstsubstrate over which the antenna is formed and a second substrate overwhich an element layer having a thin film transistor is formed over aseparation layer are attached to each other to electrically connect theantenna to the thin film transistor; the attached first and secondsubstrates are selectively removed to form an opening portion; thesecond substrate over which the element layer and the antenna areprovided is separated from the first substrate; and the second substrateover which the element layer and the antenna are provided are sealed byusing a first flexible film and a second flexible film.

In another aspect of the present invention regarding a method formanufacturing a semiconductor device, a conductive film is formed over afirst substrate; and then the conductive film is irradiated with a laserto form an antenna over the first substrate. Thereafter, the firstsubstrate over which the antenna is formed and a second substrate overwhich an element layer having a thin film transistor is formed over aseparation layer are attached to each other to electrically connect theantenna to the thin film transistor. Then, only the first substratewhich is attached to the second substrate is ground; the ground firstsubstrate is polished; and the polished first substrate and the secondsubstrate are sealed by using a first flexible film and a secondflexible film.

In another aspect of the present invention regarding a method formanufacturing a semiconductor device, in the above structure, theconductive film is formed by CVD, sputtering, plating, or evaporation.

In another aspect of the present invention regarding a method formanufacturing a semiconductor device, in the above structure, a solidlaser having a wavelength of 1 nm or more and 380 nm or less is used asthe laser.

In this specification, the “fluid” indicates a material in a statehaving fluidity.

In the present invention, since an antenna is formed by being irradiatedwith a laser, a width between lines of the antenna can be reduced to20±5 μm, which can be dramatically narrower than that of an antennaformed by a conventional method without using a mask. Therefore, when anantenna is formed in a predetermined area, a width of the antenna can beincreased or the winding number can be increased, making it possible toreduce resistance of the antenna and improve a communication distance ofa wireless chip. Further, since processing time required for forming anantenna can be drastically shortened as compared with a method by whichan object is patterned by using a mask made from a resist, throughput isimproved. Moreover, a substrate having a surface with concavity andconvexity or a substrate having a curved surface can be used as anobject (a substrate) over which an antenna is formed in addition to asubstrate having a flat surface, and therefore, there are highexpectations for its application in various industrial fields inaddition to the semiconductor field. In this specification, “patterning”indicates treatment by which an object is etched into a desired shape.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A to 1C are cross sectional views showing Embodiment Mode 1;

FIGS. 2A to 2C are cross sectional views showing Embodiment Mode 1;

FIG. 3 is a cross sectional view showing Embodiment Mode 1;

FIGS. 4A and 4B are cross sectional views showing Embodiment Mode 1;

FIGS. 5A and 5B are cross sectional views showing Embodiment Mode 1;

FIGS. 6A and 6B are cross sectional views showing Embodiment Mode 1;

FIGS. 7A and 7B are cross sectional views showing Embodiment Mode 2;

FIGS. 8A and 8B are cross sectional views showing Embodiment Mode 2;

FIGS. 9A and 9B are cross sectional views showing Embodiment Mode 2;

FIGS. 10A and 10B are cross sectional views showing Embodiment Mode 2;

FIGS. 11A to 11C are cross sectional views showing Embodiment Mode 3;

FIGS. 12A to 12C are diagrams showing Embodiment Mode 5;

FIG. 13 is a diagram showing Embodiment Mode 6;

FIGS. 14A to 14H are diagrams showing Embodiment Mode 6;

FIGS. 15A to 15D are diagrams showing Embodiment Mode 4;

FIGS. 16A to 16C are cross sectional views showing Embodiment Mode 4;and

FIGS. 17A to 17C are diagrams showing Embodiment Mode 4.

DETAILED DESCRIPTION OF THE INVENTION Embodiment Modes

The embodiment modes of the present invention will be described below.It is easily understood by those skilled in the art that the embodimentmodes and details herein disclosed can be modified in various wayswithout departing from the purpose and the scope of the invention. Thepresent invention should not be interpreted as being limited to thedescription of the embodiment modes to be given below. Further, in thestructure of the present invention, reference numerals indicating thesame things are commonly used in the drawings.

Embodiment Mode 1

In this embodiment mode, an example of a method for manufacturing asemiconductor device of the present invention will be described withreference to the drawings.

First, a separation layer 12 is formed over a surface of a substrate 11(FIG. 1A).

The substrate 11 is removed in the subsequent step, and can be formedusing a glass substrate, a quartz substrate, a ceramic substrate, or thelike. Further, a metal substrate containing stainless steel, a siliconsubstrate, or a semiconductor substrate having a surface over which aninsulating film is formed, may also be used as the substrate 11.Furthermore, a flexible substrate typified by a synthetic resin such asacrylic can be used. Preferably, a glass substrate, a plastic substrate(for example, an acrylic substrate) having a heat resistance property,which can withstand heating treatment in a process of manufacturing asemiconductor device, or the like may be used. As the plastic substratehaving the heat resistance property, polyethylene terephthalate (PET),polyethylene naphthalate (PEN), polyether sulfonate (PES), and the likecan be given as examples. Such a substrate is not limited to its area orshape; and therefore, when a rectangular substrate with 1 m or more on aside is used as the substrate 11, for example, productivity can bedrastically improved. This point is a greater advantage as compared witha case of using a circular silicon substrate. In this embodiment mode, aglass substrate is used as the substrate 11.

Next, formation of the separation layer 12 will be described in detail.

First, a metal film is formed over the substrate 11. The metal film maybe formed by a single layer or by stacking a plurality of layers. Notethat an insulating film may be provided over the substrate 11 prior toforming the separation layer 12. In particular, when there is a concernthat contamination is generated from the substrate, an insulating filmis preferably formed between the substrate 11 and the separation layer12. An insulating film provided between the substrate 11 and theseparation layer 12 can be formed to have a single layer structure of aninsulating film having at least oxygen or nitrogen such as silicon oxide(SiOx), silicon nitride (SiNx), a silicon oxide film containing nitrogen(an SiO_(x)N_(y) film) (x>y, x and y are positive integers), and asilicon nitride film containing oxygen (an SiN_(x)O_(y) film) (x>y, xand y are positive integers); or a stacked layer structure thereof.These insulating films can be formed by sputtering or various types ofCVD such as plasma CVD. In this embodiment mode, a silicon oxide filmcontaining nitrogen with a thickness of 50 to 150 nm is formed as aninsulating film provided between the substrate 11 and the separationlayer 12.

The metal film is formed to be a single layer or a stacked layer of afilm made from an element selected from tungsten (W), molybdenum (Mo),titanium (Ti), tantalum (Ta), niobium (Nb), nickel (Ni), cobalt (Co),zirconium (Zr), zinc (Zn), ruthenium (Ru), rhodium (Rh), palladium (Pd),osmium (Os), and iridium (Ir); or an alloy material or a compoundmaterial mainly containing the element. These materials can be formed bysputtering or various types of CVD such as plasma CVD. In thisembodiment mode, as the metal film, tungsten (W) is formed to have athickness of 20±5 nm by sputtering.

Next, a metal oxide film is formed over the metal film. As an example ofa method for forming the metal oxide film, a method by which a metaloxide film is directly formed by sputtering; and a method by which ametal oxide film is formed by oxidizing a surface of the metal filmprovided over the substrate 11 through heat treatment or plasmatreatment under an oxygen atmosphere; can be given. Preferably, thesurface of the metal film is subjected to high-density plasma treatmentunder an oxygen atmosphere to form a metal oxide film over the surfaceof the metal film. For example, in a case where a tungsten film with athickness of 20 to 40 nm is formed by sputtering as the metal film, thetungsten film is subjected to high-density plasma treatment so as toform a metal oxide film made from oxide of tungsten with a thickness of1 to 20 nm over the surface of the tungsten film.

In this specification, the “high-density plasma treatment” indicatestreatment in which an electron density of plasma is 1×10¹¹ cm⁻³ or moreand 1×10¹³ cm⁻³ or less, and an electron temperature of plasma is 0.5 eVor more and 1.5 eV or less. Since the electron temperature in thevicinity of an object (a metal film) formed over a substrate is lowwhile the electron density of plasma is high, damage due to plasma ofthe substrate can be prevented. Further, since the electron density ofplasma is as high as 1×10¹¹ cm⁻³ or more, a dense film with a uniformthickness, which is formed of oxide generated by oxidation treatment,can be formed. Further, the electron temperature of plasma is as low as1.5 eV or less, and therefore, oxidation treatment can be performed at alower temperature as compared with plasma treatment or thermaloxidation. For example, even when plasma treatment is performed at atemperature lower than a strain point of the glass substrate by about100° C. or more (for example, 250 to 550° C.), plasma oxidationtreatment can be sufficiently performed. Note that, as a power supplyfrequency for generating plasma, a microwave (2.45 GHz) is used.Further, potential of plasma is as low as 5 V or less so that excessivedissociation of molecules of a raw material can be suppressed.

In this embodiment mode, by performing high-density plasma treatmentunder the oxygen atmosphere to tungsten (W), which is used as the metalfilm, a metal oxide film is formed over the surface of the metal film.In a plasma condition, an electron density in the vicinity of thesubstrate is 1×10¹¹ cm⁻³ or more and 1×10¹³ cm⁻³ or less, and anelectron temperature of plasma is 0.5 eV or more and 1.5 eV or less.Further, as an atmosphere containing oxygen, a mixed gas of oxygen (O₂)or dinitrogen monoxide (N₂O) and a rare gas, or a mixed gas of oxygen(O₂) or dinitrogen monoxide (N₂O), a rare gas, and hydrogen (H₂) can beused. As the rare gas, argon (Ar), xenon (Xe), krypton (Kr), and thelike can be given. Further, a pressure ratio (or a flow ratio) ofrespective gases contained in the mixed gas may be appropriatelydetermined. A metal oxide film formed under this condition becomes afilm containing a rare gas element. Since the electron temperature islow (1.5 eV or less) and the electron density is high (1.0×10¹¹ cm⁻³ ormore), an oxide film can be formed at a low temperature with extremelyless plasma damage.

As a combination example of a mixed gas, oxygen (or dinitrogen monoxide)may be set to be 0.1 to 100 sccm, and argon may be set to be 100 to5,000 sccm. Another combination example of a mixed gas, oxygen (ordinitrogen monoxide) may be set to be 0.1 to 100 sccm; hydrogen, 0.1 to100 sccm; and argon, 100 to 5,000 sccm. The mixed gas is preferablyintroduced at a flow ratio of oxygen (or dinitrogenmonoxide):hydrogen:argon=1:1:100. For example, a mixed gas, in whichoxygen (or dinitrogen monoxide) is 5 sccm, hydrogen is 5 sccm, and argonis 500 sccm, may be introduced. Introducing hydrogen in a mixed gas ispreferable since processing time of oxidation can be shortened.

When a metal oxide film is formed by performing the high-density plasmatreatment to the surface of the metal film under an oxygen atmosphere, aseparation layer having the metal oxide film with a superior uniformthickness can be formed even though the metal oxide film is as thin as20 nm or less. Therefore, the separation layer is not disconnected inthe subsequent step so that a semiconductor device with high reliabilitycan be manufactured. Furthermore, since the separation layer having themetal oxide film with uniform thickness can be formed, a problem inwhich the separation layer is not provided on a part of a substrate andthe substrate cannot be separated can be prevented.

Through the above described steps, the separation layer 12 including themetal film and the metal oxide film can be formed. Further, in thisembodiment mode, as the separation layer 12, a stacked layer structureincluding the metal film and the metal oxide film is shown; however, thepresent invention is not limited thereto. For example, only the metaloxide film may be used as the separation layer 12.

Next, a base film 13 is formed over the separation layer 12 (FIG. 1B).As the base film 13, a single layer may be provided or a plurality offilms may be stacked. The base film 13 has a function of preventingalkali metal such as sodium (Na) contained in the substrate frompenetrating into an element such as a thin film transistor contained inan element layer 14, which will be formed later. Therefore, the basefilm 13 is not necessarily provided depending on a kind of a substrate.

The base film 13 can be formed by sputtering or various types of CVDsuch as plasma CVD to have a single layer structure of an insulatingfilm having at least oxygen or nitrogen such as silicon oxide (SiOx),silicon nitride (SiNx), a silicon oxide film containing nitrogen (anSiO_(x)N_(y) film) (x>y, x and y are positive integers), and a siliconnitride film containing oxygen (an SiN_(x)O_(y) film) (x>y, x and y arepositive integers); or a stacked layer structure thereof. For example,in a case where the base film 13 is formed to have a two layerstructure, it is preferable that a silicon nitride film containingoxygen be formed as a first insulating film and a silicon oxide filmcontaining nitrogen be formed as a second insulating film. Further, in acase where the base film 13 is formed to have a three layer structure,it is preferable that a silicon oxide film containing nitrogen be formedas a first insulating film, a silicon nitride film containing oxygen beformed as a second insulating film, and a silicon oxide film containingnitrogen be formed as a third insulating film. Alternatively, it ispreferable that a silicon oxide film be formed as a first insulatingfilm, a silicon nitride film containing oxygen be formed as a secondinsulating film, and a silicon oxide film containing nitrogen be formedas a third insulating film. In this embodiment mode, the base film 13 isformed to have a two layer structure including a silicon nitride filmcontaining oxygen and a silicon oxide film containing nitrogen formedover the silicon nitride film containing oxygen.

Next, a layer 14 in which an element such as a thin film transistor isprovided (hereinafter, referred to as “an element layer 14”) is formedover the base film 13. In this specification, the “element layer”indicates a layer in which at least an element typified by a thin filmtransistor (TFT) is provided. By using an element such as a thin filmtransistor, various kinds of integrated circuits such as a CPU (centralprocessing unit), a memory, and a microprocessor can be provided. Notethat a structure having an antenna together with a thin film transistorwill be described as the element layer 14 in this embodiment mode.

Next, an example of a method for forming the element layer 14, will bedescribed.

First, an amorphous semiconductor film (for example, a film mainlycontaining amorphous silicon) 704 is formed over the base film 13 (FIG.1C). The amorphous semiconductor film 704 is formed to have a thicknessof 25 to 200 nm (preferably, 30 to 150 nm) by sputtering or varioustypes of CVD such as plasma CVD. Subsequently, the amorphoussemiconductor film 704 is crystallized to form a crystallinesemiconductor film. As a crystallization method, laser crystallization,thermal crystallization using RTA or an annealing furnace, thermalcrystallization using a metal element for promoting crystallization,thermal crystallization using a metal element for promotingcrystallization with laser crystallization, or the like can be used.Thereafter, the thus obtained crystalline semiconductor film ispatterned into a desired shape to form crystalline semiconductor films706 to 710 (FIG. 2A). Note that the separation layer 12, the base film13, and the amorphous semiconductor film 704 can be successively formedwithout being exposed to atmospheric air.

An example of steps of manufacturing the crystalline semiconductor films706 to 710 is briefly described below. As a method for crystallizing theamorphous semiconductor films, laser crystallization, thermalcrystallization using RTA or an annealing furnace, thermalcrystallization using a metal element for promoting crystallization,thermal crystallization using a metal element for promotingcrystallization with laser crystallization, or the like can be given.Further, as another crystallization method, crystallization may beperformed by generating thermal plasma by applying DC bias and makingthe thermal plasma affect a semiconductor film.

In this embodiment mode, an amorphous semiconductor film with athickness of 40 to 300 nm is formed by plasma CVD, and then theamorphous semiconductor film is crystallized by heat treatment to formthe crystalline semiconductor films 706 to 710. As the heat treatment, alaser heating furnace, laser irradiation, or irradiation of lightemitted from a lamp instead of laser beam (hereinafter, referred to aslamp annealing), or a combination thereof can be used.

When employing laser irradiation, a continuous wave laser beam (CW laserbeam) or a pulsed laser beam (pulse laser beam) can be used. As a usablelaser beam, a beam emitted from one or plural kinds of a gas laser suchas an Ar laser, a Kr laser, or an excimer laser; a laser using, as amedium, single crystalline YAG, YVO₄, forsterite (Mg₂SiO₄), YAlO₃, orGdVO₄ or polycrystalline (ceramic) YAG, Y₂O₃, YVO₄, YAlO₃, or GdVO₄doped with one or more of Nd, Yb, Cr, Ti, Ho, Er, Tm, and Ta as adopant; a glass laser; a ruby laser; an alexandrite laser; a Ti:sapphire laser; a copper vapor laser; and a gold vapor laser, can beused. An object is irradiated with a laser beam having a fundamentalwave of such lasers or a second to a fourth harmonic of a fundamentalwave to obtain a crystal with a large grain size. For instance, thesecond harmonic (532 nm) or the third harmonic (355 nm) of an Nd:YVO₄laser (fundamental wave of 1,064 nm) can be used. In this case, thepower density of about 0.01 to 100 MW/cm² (preferably, 0.1 to 10 MW/cm²)is required for a laser. The scanning rate is approximately set to beabout 10 to 2,000 cm/sec to irradiate the semiconductor film.

Note that each laser using, as a medium, single crystalline YAG, YVO₄,forsterite (Mg₂SiO₄), YAlO₃, or GdVO₄ or polycrystalline (ceramic) YAG,Y₂O₃, YVO₄, YAlO₃, or GdVO₄ doped with one or more of Nd, Yb, Cr, Ti,Ho, Er, Tm, and Ta as a dopant; an Ar ion laser; and a Ti: sapphirelaser, can continuously oscillate. Further, pulse oscillation thereofcan be performed with an oscillation frequency of 10 MHz or more bycarrying out Q switch operation or mode synchronization. When a laserbeam is oscillated with an oscillation frequency of 10 MHz or more, asemiconductor film is irradiated with a next pulse during a period wherethe semiconductor film is melted by the laser beam and then issolidified. Therefore, differing from a case of using a pulse laser witha low oscillation frequency, a solid-liquid interface can becontinuously moved in the semiconductor film so that crystal grains,which continuously grow toward a scanning direction, can be obtained.

When the amorphous semiconductor film is crystallized by using acontinuous wave laser or a laser beam which oscillates at a frequency of10 MHz or more as described above, a surface of the crystallizedsemiconductor film can be planarized. As a result, a gate insulatingfilm 705, which will be formed later, can be formed thinly. In addition,this contributes to improve pressure resistance of the gate insulatingfilm.

When ceramic (polycrystal) is used as a medium, the medium can be formedto have a free shape for a short time at low cost. When using a singlecrystal, a columnar medium with several mm in diameter and several tensof mm in length is usually used. In the case of using the ceramic, amedium bigger than the case of using the single crystal can be formed.

A concentration of a dopant such as Nd or Yb in a medium, which directlycontributes to light emission, cannot be changed largely in both casesof the single crystal and the polycrystal, and therefore, there is alimitation in improvement in output of a laser by increasing theconcentration of the dopant to some extent. However, in the case of theceramic, the size of a medium can be significantly increased as comparedwith the case of the single crystal, and therefore, drastic improvementin output of a laser can be expected.

Further, in the case of the ceramic, a medium with a parallelepipedshape or a rectangular parallelepiped shape can be easily formed. In acase of using a medium having such a shape, when oscillated light ismade travel in a zig-zag manner inside the medium, a path of theoscillated light can be made long. Therefore, amplitude is increased anda laser beam can be oscillated at high output. Furthermore, a crosssection of a laser beam emitted from a medium having such a shape has aquadrangular shape, and therefore, as compared with a laser beam with acircular shape, the laser beam with the quadrangular shape in crosssection have an advantage to be shaped into a linear beam. By shaping alaser beam emitted in the above described manner using an opticalsystem, a linear beam with 1 mm or less in length of a short side andseveral mm to several m in length of a long side can be easily obtained.In addition, when a medium is uniformly irradiated with excited light, alinear beam is emitted with a uniform energy distribution in a long sidedirection.

When a semiconductor film is irradiated with this linear beam, thesemiconductor film can be uniformly annealed. In a case where uniformannealing is required from one end to the other end of the linear beam,an arrangement in which slits are provided in both ends of the linearbeam so as to shield an attenuated portion of energy of the linear beam,or the like may be performed.

When a semiconductor film is annealed by using the thus obtained linearbeam with uniform intensity and a semiconductor device is manufacturedby using this semiconductor film, a characteristic of the semiconductordevice can be made favorable and uniform.

As thermal crystallization using a metal element for promotingcrystallization, an example of a specific method will be given. Afterkeeping a solution containing nickel, which is a metal element forpromoting crystallization, over an amorphous semiconductor film, theamorphous semiconductor film is subjected to dehydrogenation treatment(500° C. for one hour) and thermal crystallization treatment (550° C.for four hours) so as to form a crystalline semiconductor film.Thereafter, the crystalline semiconductor film is irradiated with alaser beam if required, and then, the crystalline semiconductor film ispatterned by photolithography to form the crystalline semiconductorfilms 706 to 710.

The thermal crystallization using a metal element for promotingcrystallization has advantages of being capable of crystallizing anamorphous semiconductor film at a low temperature for a short time andaligning a direction of crystals; however, the thermal crystallizationhas drawbacks that off current is increased due to a remaining metalelement in the crystalline semiconductor film and characteristics of thecrystalline semiconductor film are not stabilized. Therefore, it ispreferable to form an amorphous semiconductor film serving as agettering site over the crystalline semiconductor film. Since theamorphous semiconductor film, which becomes the gettering site, isnecessary to contain an impurity element such as phosphorus or argon,the amorphous semiconductor film is preferably formed by sputtering bywhich the amorphous semiconductor film can contain argon at a highconcentration. Thereafter, heat treatment (RTA, thermal annealing usingan annealing furnace, or the like) is performed to disperse the metalelement in the amorphous semiconductor film. Subsequently, the amorphoussemiconductor film containing the metal element is removed. By carryingout such gettering process, the amount of the metal element contained inthe crystalline semiconductor film can be reduced or the metal elementcan be removed.

Next, a gate insulating film 705 is formed to cover the crystallinesemiconductor films 706 to 710. The gate insulating film 705 is formedby using a single layer or a stacked layer containing silicon oxide orsilicon nitride by sputtering or various types of CVD such as plasmaCVD. Specifically, the gate insulating film 705 is formed by using asingle layer of a film containing silicon oxide, a film containingsilicon oxynitride, or a film containing silicon nitride oxide, or byappropriately stacking these films. Alternatively, the crystallinesemiconductor films 706 to 710 may be subjected to the above describedhigh-density plasma treatment under an atmosphere containing oxygen,nitrogen, or both of oxygen and nitrogen to oxidize or nitride eachsurface of the crystalline semiconductor films 706 to 710 so as to formthe gate insulating film. The gate insulating film formed by thehigh-density plasma treatment has superior uniformity in film thicknessand film quality as compared with a film formed by CVD or sputtering. Inaddition, a dense film can be formed as the gate insulating film by thehigh-density plasma treatment. As an atmosphere containing oxygen, amixed gas of oxygen (O₂), nitrogen dioxide (NO₂) or dinitrogen monoxide(N₂O), and a rare gas; or a mixed gas of oxygen (O₂), nitrogen dioxide(NO₂) or dinitrogen monoxide (N₂O), a rare gas, and hydrogen (H₂); canbe used. Further, as an atmosphere containing nitrogen, a mixed gas ofnitrogen (N₂) or ammonia (NH₃) and a rare gas; or a mixed gas ofnitrogen (N₂) or ammonia (NH₃), a rare gas, and hydrogen (H₂); can beused. Each surface of the crystalline semiconductor films 706 to 710 canbe oxidized or nitrided by oxygen radical (which contains OH radical insome cases) or nitrogen radical (which contains NH radical in somecases) generated by high-density plasma.

When the gate insulating film 705 is formed by the high-density plasmatreatment, an insulating film with a thickness of 1 to 20 nm, andtypically, 5 to 10 nm, is formed over the crystalline semiconductorfilms 706 to 710. A reaction in this case is a solid-phase reaction, andtherefore, interface state density between the insulating film and thecrystalline semiconductor films 706 to 710 can be extremely reduced.Further, since the crystalline semiconductor films 706 to 710 can bedirectly oxidized or nitrided, variations in thickness of the gateinsulating film 705 to be suppressed significantly and ideally.Furthermore, since strong oxidation is not generated in a crystal grainboundary of crystalline silicon, an extremely preferable state is made.That is, when each surface of the crystalline semiconductor films issubjected to solid-phase oxidation by the high-density plasma treatmentshown here, an insulating film with low interface state density and gooduniformity can be formed without generating abnormal oxidation reactionin a crystal grain boundary.

Note that, as the gate insulating film 705, only an insulating filmformed through the high-density plasma treatment may be used.Alternatively, the insulating film formed through the high-densityplasma treatment and another insulating film including silicon oxide,silicon nitride containing oxygen, or silicon oxide containing nitrogenby CVD utilizing plasma or a thermal reaction may be stacked to form thegate insulating film 705. In either case, when a transistor is formed tohave a gate insulating film which partly or entirely includes aninsulating film formed by high-density plasma, variations incharacteristics can be reduced.

Further, the crystalline semiconductor films 706 to 710 formed bycrystallizing the amorphous semiconductor film 704 by irradiation of acontinuous wave laser beam or a laser beam oscillated at a frequency of10 MHz or more while scanning the amorphous semiconductor film with thelaser beam in one direction, have a characteristic that crystals grow ina scanning direction of the laser beam. Therefore, when a transistor isdisposed such that the scanning direction corresponds to a channellength direction (a direction of flowing carries when a channelformation region is formed) and the gate insulating film 705 formed bythe high-density plasma treatment is combined with the transistor, atransistor with less variations in characteristics and high electronfield-effect mobility can be obtained.

Next, a first conductive film and a second conductive film are stackedover the gate insulating film 705. The first conductive film and thesecond conductive film may be formed by sputtering or various types ofCVD such as plasma CVD. In this embodiment mode, the first conductivefilm is formed to have a thickness of 20 to 100 nm, whereas the secondconductive film is formed to have a thickness of 100 to 400 nm. Further,the first conductive film and the second conductive film can be formedby using an element selected from tantalum (Ta), tungsten (W), titanium(Ti), molybdenum (Mo), aluminum (Al), copper (Cu), chromium (Cr),niobium (Nb), and the like; or an alloy material or a compound materialmainly containing these elements. Further, the first and secondconductive films can be formed by using a semiconductor materialtypified by polycrystalline silicon doped with an impurity element suchas phosphorus. As a combination of the first conductive film and thesecond conductive film, a tantalum nitride (TaN) film and a tungsten(1N) film; a tungsten nitride (WN) film and a tungsten film; amolybdenum nitride (MoN) film and a molybdenum (Mo) film; and the likecan be given. Since tungsten and tantalum nitride have high heatresistance properties, after forming the first and second conductivefilms using tungsten or tantalum nitride, heat treatment for thermalactivation can be carried out. Further, a single layer structure or athree layer structure may be employed instead of the two layer structureof the first and second conductive films. In a case of a three layerstructure, it is preferable to employ a structure in which a molybdenumfilm, an aluminum film, and another molybdenum film are sequentiallystacked from a substrate side; or a structure in which a titanium film,an aluminum film, and another titanium film are sequentially stackedfrom the substrate side.

Next, a mask is formed using a resist by photolithography. Whileutilizing the mask, etching treatment is performed to form gateelectrodes and gate wirings so as to form conductive films 716 to 725serving as gate electrodes (hereinafter, sometimes referred to as “gateelectrodes” in this specification).

Next, after forming a mask using a resist by photolithography, animpurity element imparting N-type conductivity is added at a lowconcentration to the crystalline semiconductor films 706 and 708 to 710by ion doping or ion implantation. In this manner, N-type impurityregions 711 and 713 to 715 and channel formation regions 780 and 782 to784 are formed. As the impurity element imparting the N-typeconductivity, an element belonging to Group 15 of the periodic table maybe used, and for example, phosphorus (P) or arsenic (As) is used.

Next, a mask is formed using a resist by photolithography. Whileutilizing the mask, an impurity element imparting P-type conductivity isadded to the crystalline semiconductor film 707 to form a P-channelimpurity region 712 and a channel formation region 781. As the impurityelement imparting the P-type conductivity, for example, boron (B) isused. Note that after forming the N-type impurity regions 711 and 713 to715, the P-type impurity region 712 may be formed in the same manner asthis embodiment mode. Alternatively, after forming the P-type impurityregion 712, the N-type impurity regions 711 and 713 to 715 may beformed.

Subsequently, an insulating film is formed to cover the gate insulatingfilm 705 and the conductive films 716 to 725. The insulating film isformed using a single layer or a stacked layer of a film made from aninorganic material such as silicon, silicon oxide, or silicon nitride ora film made from an organic material such as an organic resin bysputtering or various types of CVD such as plasma CVD. Then, theinsulating film is selectively etched by anisotropic etching mainly in aperpendicular direction to form insulating films (also, referred to assidewalls) 739 to 743 being in contact with side surfaces of theconductive films 716 to 725 (FIG. 2B). At the same time of forming theinsulating films 739 to 743, insulating films 734 to 738 are formed byetching the gate insulating film 705. The insulating films 739 to 743will be used as masks for doping when forming an LDD (lightly dopeddrain) region.

Next, by using a mask formed using a resist by photolithography and theinsulating films 739 to 743 as masks, an impurity element impartingN-type conductivity is added to the crystalline semiconductor films 706and 708 to 710 to form first N-type impurity regions (LDD regions) 727,729, 731, and 733 and second N-type impurity regions 726, 728, 730, and732. A concentration of the impurity element contained in the firstN-type impurity regions 727, 729, 731, and 733 is lower than that of theimpurity element contained in the second N-type impurity regions 726,728, 730, and 732. Through the above described steps, N-type thin filmtransistors 744 and 746 to 748, and a P-type thin film transistor 745are completed.

In order to form an LDD region, there is a technique in which a gateelectrode having a stacked structure including two or more layers isformed, etching by which the gate electrode is tapered or anithotropicetching is performed, and a conductive film of a lower layer of the gateelectrode is used as a mask; and a technique in which an insulating filmof a sidewall is used as a mask. A thin film transistor formed by usingthe former technique has a structure in which an LDD region isoverlapped with the gate electrode with the gate insulating filminterposed therebetween. However, since the etching by which the gateelectrode is tapered or the anisotropic etching is used in thisstructure, it is difficult to control a width of the LDD region, andtherefore, an LDD region sometimes cannot be formed without a properetching step. On the other hand, the latter technique using theinsulating film of the sidewall as a mask can control a width of an LDDregion more easily as compared with the former technique, so that theLDD region can be certainly formed. Note that “the etching by which thegate electrode is tapered” indicates etching by which a side surface ofthe gate electrode is made to have a tapered shape.

After removing an oxide film, which is naturally formed over exposedsurfaces of the N-type impurity regions 726, 728, 730, and 732 and theP-type impurity region 785, silicide regions may be arbitrarily formedby using a metal film. As the metal film, a film made from nickel,titanium, cobalt, or platinum; a film made from an alloy containing atleast two kinds of these elements; or the like can be used.Specifically, a nickel film is used as the metal film, for example. Thenickel film is formed by sputtering at power of 500 W to 1 kW under aroom temperature, and then a silicide region is formed by heattreatment. The heat treatment can employ RTA, an annealing furnace, orthe like. In this case, by controlling a thickness of the metal film, aheating temperature, and a heating time, silicide regions may be formedonly over the surfaces of the N-type impurity regions 726, 728, 730, and732 and the P-type impurity region 785. Alternatively, a silicide regioncan be formed over an entire surface of the substrate. Then, nickel,which is unreacted, is removed. For example, the unreacted nickel isremoved by using an etching solution of HC1:HNO₃:H₂O=3:2:1.

Note that this embodiment mode shows an example in which the thin filmtransistors 744 to 748 are of a top-gate type; however, it is obviousthat each of the thin film transistors may be a bottom-gate thin filmtransistor. Further, a single gate structure in which a single channelformation region is formed in each of the thin film transistors 744 to748, is described in this embodiment mode. Alternatively, a double gatestructure in which two channel formation regions are formed in each ofthe thin film transistors or a triple gate structure in which threechannel formation regions are formed in each of the thin filmtransistors may be employed. Moreover, a dual gate structure having twogate electrodes which are disposed over and under a channel formationregion through a gate insulating film, or other structure may beemployed.

Each of the thin film transistors 744 to 748 may have a structure otherthan the structure described in this embodiment mode. For example, eachof the thin film transistors may have an impurity region (including asource region, a drain region, and an LDD region). Alternatively, eachof the thin film transistors may be a P-channel TFT, an N-channel TFT,or a CMOS circuit. Further, an insulating film (a sidewall) may beformed to be in contact with a side surface of a gate electrode providedover or under the semiconductor film.

After completing the N-type thin film transistors 744 and 746 to 748 andthe P-type thin film transistor 745 through the above described steps,heat treatment for recovering crystallinity of the semiconductor filmsor activating the impurity elements added to the semiconductor films,may be performed. Further, after performing the heat treatment, theexposed gate insulating film 705 is preferably subjected to high-densityplasma treatment under an atmosphere containing hydrogen so that asurface of the gate insulating film 705 may contain hydrogen. This isbecause the hydrogen can be utilized when performing a step ofhydrogenating the semiconductor film later. Further, by performinghigh-density plasma treatment under an atmosphere containing hydrogenwhile heating the substrate at 350 to 450° C., hydrogenation of thesemiconductor film can be performed. Further, as the atmospherecontaining hydrogen, a mixed gas of hydrogen (H₂) or ammonia (NH₃) and arare gas (for example, argon (Ar)) can be used. When a mixed gas ofammonia (NH₃) and a rare gas (for example, argon (Ar)) is used as theatmosphere containing hydrogen, the surface of the gate insulating film705 can be hydrogenated and nitrided at the same time.

Then, a single layer or a stacked layer of an insulating film is formedto cover the thin film transistors 744 to 748 (FIG. 2C). The insulatingfilm covering the thin film transistors 744 to 748 is formed using asingle layer or a stacked layer made from an inorganic material such assilicon oxide or silicon nitride, an organic material such as polyimide,polyamide, benzocyclobutene, acrylic, epoxy, or siloxane, or the like,by an SOG technique, a droplet discharging method, or the like. In thisspecification, siloxane has a skeleton structure including silicon(Si)-oxygen (O) bonds and an organic group containing at least hydrogen(for example, an alkyl group, or aromatic hydrocarbon) is used as asubstituent. Further, as the substituent, a fluoro group may be used, orboth of an organic group containing at least hydrogen and a fluoro groupmay be used. For example, in a case where the insulating film coveringthe thin film transistors 744 to 748 has a three layer structure, a filmmainly containing silicon oxide may be formed as a first insulating film749, a film mainly containing a resin may be formed as a secondinsulating film 750, and a film mainly containing silicon nitride may beformed as a third insulating film 751. Further, in a case where theinsulating film covering the thin film transistors 744 to 748 has asingle layer structure, a silicon nitride film or a silicon nitride filmcontaining oxygen may be formed. In this case, it is preferable that byperforming high-density plasma treatment under an atmosphere containinghydrogen with respect to the silicon nitride film or the silicon nitridefilm containing oxygen, hydrogen be contained in a surface of thesilicon nitride film or the silicon nitride film containing oxygen. Thisis because the hydrogen can be utilized when performing a step ofhydrogenating the semiconductor films later. Further, by performinghigh-density plasma treatment under an atmosphere containing hydrogenwhile heating the substrate at 350 to 450° C., hydrogenation of thesemiconductor film can be performed. Note that, as the atmospherecontaining hydrogen, a mixed gas of hydrogen (H₂) or ammonia (NH₃) and arare gas (for example, argon (Ar)) can be used. When a mixed gas ofammonia (NH₃) and a rare gas (for example, argon (Ar)) is used as theatmosphere containing hydrogen, the surface of the gate insulating film705 can be simultaneously hydrogenated and nitrided.

Note that, prior to forming the insulating films 749 to 751, or afterforming one or a plurality of thin films of the insulating films 749 to751, heat treatment for recovering crystallinity of the semiconductorfilms, activating the impurity elements added to the semiconductorfilms, or hydrogenating the semiconductor films, may be performed. Theheat treatment may use thermal annealing, laser annealing, RTA, or thelike. For example, in order to activate the impurity elements, thermalannealing at 500° C. or more may be performed. Further, in order tohydrogenate the semiconductor films, thermal annealing at 350 to 450° C.may be performed.

Next, the insulating films 749 to 751 are etched by photolithography toform contact holes through which the N-type impurity regions 726, 728,730, and 732 and the P-type impurity region 785 are exposed.Subsequently, a conductive film is formed to fill the contact holes. Theconductive film is patterned to form conductive films 752 to 761 eachserving as a source wiring or a drain wiring.

The conductive films 752 to 761 are formed by using a conductive filmmainly containing aluminum (Al) by sputtering, various types of CVD suchas plasma CVD, or the like. The conductive film mainly containingaluminum (Al) corresponds to a material mainly containing aluminum,which also contains nickel, or an alloy material mainly containingaluminum, which also contains nickel and one or both of carbon andsilicon, for example. Since the conductive film mainly containingaluminum generally has a drawback of a poor heat resistance property,the conductive film mainly containing aluminum is preferably sandwichedbetween barrier films. The barrier films indicate films having afunction of suppressing heroic of the conductive film mainly containingaluminum or improving a heat resistance property. As a material havingsuch a function, chromium, tantalum, tungsten, molybdenum, titanium,silicon, and nickel, or nitride of these elements can be given. As anexample of a structure of each of the conductive films 752 to 761, astructure in which a titanium film, an aluminum film, and anothertitanium film are sequentially stacked from a substrate side, can begiven. Since titanium is an element having a high reducing property,even when a thin oxide film is naturally formed on the crystallinesemiconductor films, the oxide film naturally formed can be reduced bythe titanium so as to make good contact to the crystalline semiconductorfilms. Further, the titanium film formed between the crystallinesemiconductor films and the aluminum film, is preferably subjected tohigh-density plasma treatment under an atmosphere containing nitrogen tonitride a surface of the titanium film. In a condition of thehigh-density plasma treatment, electron density of plasma is 1×10¹¹ cm⁻³or more and 1×10¹³ cm⁻³ or less, and an electron temperature of plasmais 0.5 eV or more and 1.5 eV or less. As the atmosphere containingnitrogen, a mixed gas of N₂ or NH₃ and a rare gas, or a mixed gas of N₂or NH₃, a rare gas, and H₂ can be used. Nitriding the surface of thetitanium film makes it possible to prevent alloying of titanium andaluminum and prevent aluminum from dispersing in the crystallinesemiconductor films through the titanium film in a subsequent heattreatment or the like. Note that an example of sandwiching the aluminumfilm with the titanium films is described here, and this is the same fora case of using chromium films, tungsten films, or the like instead ofthe titanium films. More preferably, formation of one titanium film,nitriding treatment of the surface of the titanium film, formation ofthe aluminum film, and formation of another titanium film aresuccessively carried out by using a multi-chamber apparatus withoutexposing these films to atmospheric air.

Next, an insulating film 762 is formed to cover the conductive films 752to 761 (FIG. 3). The insulating film 762 is formed to be a single layeror a stacked layer using an inorganic material or an organic material bySOG, a droplet discharging method, or the like. In this embodiment mode,the insulating film 762 is formed to have a thickness of 0.75 to 3 μm.

Next, the insulating film 762 is etched by photolithography to form acontact hole through which the conductive film 761 is exposed.Subsequently, a conductive film is formed over a top surface of theinsulating film 762 so as to fill the contact hole. As a method forforming the conductive film, for example, the conductive film can beformed using a fluid containing conductive particles by any one ofscreen printing, spin coating, dipping, a droplet discharging methodusing an ink-jet technique, or the like. Further, the conductive filmmay be formed by CVD, sputtering, plating, or evaporation. In this case,the conductive film can be formed using any one of Au, Ag, Cu, Ni, Pt,Pd, Ir, Rh, W, Al, Ta, Mo, Cd, Zn, Fe, Ti, Zr, and Ba, or an alloy or acompound thereof. Further, the conductive film can also be formed usingpolycrystalline Si or polycrystalline Ge doped with an impurity elementsuch as phosphorus.

In this embodiment mode, a method for forming the conductive film byusing screen printing will be described in detail. When the conductivefilm is formed by screen printing, a thickness of the conductive filmcan be easily made thicker as compared with a case of using anothermethod, and therefore, the screen printing is preferable. For example,as compared with a case where there is a limitation that the conductivefilm is formed to have a thickness of up to 5 μm by sputtering or aboutup to several μm by the droplet discharging method, when using screenprinting, the conductive film with a thickness of up to about 50 μm (forexample, 20 μm or more and 50 μm or less) can be formed at maximum. Byforming the thicker conductive film, resistance of a wiring, which willbe an antenna later, can be further reduced.

Conductive particles with a diameter of 1 nm or more and 100 nm or lesscan be used. In this specification, a “fluid” indicates a materialhaving fluidity, and for example, indicates a paste-like material. Asshown in FIG. 3, in the screen printing, a screen printing plate 301having a metallic mesh 304 and emulsion 305 for a mask inside of a frame303, is provided over an object. Next, a fluid 306 containing conductiveparticles is provided over the screen printing plate 301. The fluid 306containing the conductive particles is pressed and pushed out by using asqueegee 307, a roller, or the like so that the fluid is applied to asurface of an object (the insulating film 762). As a result, the fluidis applied to the top surface of the insulating film 762 to fill thecontact hole. Note that, prior to pushing out the fluid containing theconductive particles by the squeegee, the roller or the like, the fluidcontaining the conductive particles may be spread over the screenprinting plate by a scraper.

Next, the fluid 306 containing the conductive particles, which isapplied to the top surface of the insulating film 762 and inside of thecontact hole is baked and cured to form a conductive film 310. In orderto completely cure the fluid, a baking temperature of 150° C. or more isrequired. In a case of using fine particles mainly containing silver asconductive fine particles contained in the fluid, when a bakingtemperature is more than 300° C., a dense property is degraded, so thatthe fluid easily becomes a porous state with a rough surface. Therefore,the fluid is preferably baked in a temperature range of 150 to 300° C.In this embodiment mode, baking time is set to be one hour; however,baking time may be arbitrarily set such that the fluid is completelycured. Although the fluid 306 is cured by baking in this embodimentmode, when using a light curing resin as the fluid 306, the fluid 306can be cured by being irradiated with light (for example, ultravioletray, electron beam, or visible ray). That is, a method for curing thefluid is not limited to baking, and a method in which the fluid isirradiated with light can also be used. As an example of the lightcuring resin, an acrylic resin, a silicone resin, and the like can begiven.

The conductive fine particles are uniformly dispersed in the fluidwithout aggregating in a solvent. As examples of the conductive fineparticles contained in the fluid, the above mentioned fine particlesmainly containing silver can be given. Further, any material can be usedas a wiring serving as an antenna after baking. For example, fineparticles mainly containing any one of gold, silver, copper, an alloy ofgold and silver, an alloy of gold and copper, an alloy of silver andcopper, and an alloy of gold, silver, and copper, may be used. Further,fine particles mainly containing indium tin oxide (hereinafter, referredto as ITO), conductive oxide in which 2 wt % or more and 20 wt % or lesszinc oxide is mixed in indium oxide (hereinafter, referred to as IZO(indium zinc oxide)), or conductive oxide in which 2 wt % or more and 20wt % or less silicon oxide is mixed in indium oxide (hereinafter,referred to as ITSO), may be used. Further, fine particles mainlycontaining a lead-free solder may be used. In this case, fine particleswith a diameter of 20 μm or less are preferably used. As compared withthe above mentioned fine particles mainly containing silver, the fineparticles mainly containing a lead-free solder is superior in low cost.It is also possible to use fine particles mainly containing a soldercontaining lead, though environmental pollution may arise.

Next, the conductive film 310 is patterned by being irradiated with alaser to form wirings 763 to 765 (FIG. 4A). Each of the wirings 763 to765 serves as an antenna. The patterning using laser irradiation may bea physical technique (also, referred to as “laser ablation”) or achemical technique. The physical technique is a process where bonding ofatoms or molecules inside a solid (which is the conductive film in thisembodiment mode) is photodissociated by photon energy of a laser beamunder atmospheric air or an inert gas atmosphere while the conductivefilm, which is decomposed with heat generated by absorption of excessivelaser energy, is scattered. The chemical technique is a process where anobject is irradiated with a laser beam while keeping it under a reactivegas (etchant). Further, a condition or a type of a laser is notparticularly limited. For example, a continuous wave laser beam (CWlaser beam) or a pulsed wave laser beam (pulsed laser beam) can be used.As a usable laser beam, a beam emitted from one or plural kinds of a gaslaser such as an Ar laser, a Kr laser, or an excimer laser; a laserusing, as a medium, single crystalline YAG, YVO₄, forsterite (Mg₂SiO₄),YAlO₃, or GdVO₄ or polycrystalline (ceramic) YAG, Y₂O₃, YVO₄, YAlO₃, orGdVO₄ doped with one or more of Nd, Yb, Cr, Ti, Ho, Er, Tm, and Ta as adopant; a glass laser; a ruby laser; an alexandrite laser; a Ti:sapphire laser; a copper vapor laser; and a gold vapor laser, can beused. Preferably, a solid laser with a wavelength of 1 nm or more and380 nm or less may be used. In this embodiment mode, an UV laser isused.

Note that when the conductive film 310 is irradiated with a laser beamto perform the patterning (scribing), there is a possibility that theinsulating film 762 underlying the conductive film 310 is partly etchedand an element formed under the insulating film 762 is also damaged.Whether or not the insulating film 762 is etched is determined by amaterial of the insulating film 762 and a condition of laserirradiation. Therefore, in order to prevent the insulating film 762 frombeing etched, the insulating film 762 may be formed using a dense hardfilm like DLC (diamond like carbon), or a condition of laser irradiationmay be appropriately determined. Further, the insulating film 762 ispreferably formed by using a stacked structure of a planarization filmmade from an organic material and a DLC film formed over theplanarization film. When the insulating film 762 includes such a stackedstructure, unevenesses generated by the conductive films 752 to 761 canbe reduced by the planarization film and an element formed under theinsulating film 762 can be protected by the DLC film in laserirradiation. Even when the insulating film 762 is partly etched, aninsulating film may be formed over the insulating film 762. In thisembodiment mode, since an insulating film 15 is provided over theinsulating film 762 after patterning, if the surface of the insulatingfilm 762 is partly etched, no problems arise.

A width between lines of the conductive film (the antenna) manufacturedby this method is as narrow as 20±5 μm, and therefore, a region per unitarea in which the antenna can be formed, can be increased. As aconsequence, resistance of the antenna can be reduced, thereby improvinga communication distance of a wireless chip. Moreover, processing timerequired for forming the antenna can be extremely shortened as comparedwith a case of employing a patterning method using a mask made from aresist.

Further, when after forming the conductive film by using the screenprinting, the antenna is formed by patterning the conductive film withlaser irradiation, advantageous effects described below can be obtainedas compared with a case of directly forming an antenna by screenprinting. Specifically, when an antenna is directly formed by screenprinting, since a running resin is generated in steps of forming theantenna from a printing step to baking (a baking step), a cross sectionof the formed antenna has a trapezoidal shape, and therefore, resistanceof the antenna is increased. On the other hand, when after forming theconductive film by using the screen printing, the antenna is formed bypatterning the conductive film with laser irradiation, a cross sectionof the formed antenna does not easily have a trapezoidal shape, andhence, resistance of the antenna can be reduced.

The element layer 14 is completed through the above described steps.

Next, an insulating film 15 (a protection layer) is formed by SOG, adroplet discharging method, or the like so as to cover the wirings 763to 765 serving as the antenna (FIG. 4B). The insulating film 15 servesas the protection layer for securing the strength of the element layer14, and therefore, the insulating layer 15 is sometimes denoted as theprotection layer below in this specification. The insulating film 15 ispreferably formed to cover a side surface of the base film 13 and a sidesurface of the element layer 14. Although the insulating film 15 isprovided over the entire surface to cover the base film 13 and theelement layer 14 in this embodiment mode, the insulating film 15 is notnecessarily provided over an entire surface and may be providedselectively. Note that when the element layer 14 has enough strength,the insulating film 15 is not required to be provided.

The insulating film 15 may be formed by using a film containing carbonsuch as DLC (diamond like carbon), a silicon oxide film containingnitrogen, a silicon nitride film containing oxygen, a film made from aresin material such as epoxy or other organic material, or the like. Theinsulating film 15 can be formed by sputtering, various types of CVDsuch as plasma CVD, spin coating, a droplet discharging method, screenprinting, or the like.

Next, the insulating film is etched to expose the separation layer 12 toform opening portions 773 and 774 (FIG. 5A). Providing the openingportions 773 and 774 makes it possible to easily separate an elementfrom the substrate 11 in a subsequent separating step. Further, theopening portions 773 and 774 are preferably provided in a region inwhich elements such as the thin film transistors included in the elementlayer 14 are not provided or edge regions of the substrate 11. Theopenings 773 and 774 can be formed by photolithography, irradiation oflaser light (for example, UV light), or grinding and cutting of an endsurface of a sample.

Next, an etching agent is introduced in the opening portions 773 and 774to remove the separation layer 12 (FIG. 5B), if required. By removingthe separation layer 12, the element can be separated from the substrate11 more easily in the subsequent separating step; however, this step ofremoving the separation layer may be omitted. As the etching agent, agas or a liquid containing halogen fluoride is used. As a gas containinghalogen fluoride, for example, chlorine trifluoride (ClF₃) gas can beused. When the etching agent is introduced in the opening portions, theelement layer 14 can be separated from the substrate 11. Note that theelement layer 14 indicates a layer including the thin film transistors744 to 748 and the conductive film 786 serving as the antenna. Further,the separation layer 12 may be partly left rather than being removedentirely. By leaving part of the separation layer 12, consumption of theetching agent can be suppressed and a processing time required forremoving the separation layer can be shortened, thereby reducing costand realizing high efficiency. In addition, after removing theseparation layer 12, the element layer 14 can be kept over the substrate11 by part of the remaining separation layer 12.

Note that this embodiment mode employs a method in which after formingthe opening portions 773 and 774, the etching agent is introduced in theopening portions 773 and 774 to remove the separation layer 12.Alternatively, a stacked body including the base film 13, the elementlayer 14, and the protection layer 15 may be separated from thesubstrate 11 by using the other method. For example, it is possible touse a method in which after forming opening portions by using a laser ora cutter to reach the separation layer 12, the stacked body may beseparated from the substrate 11 by using a physical means. The phrase“being separated by a physical means” indicates separation caused byapplying stress from an external portion. For example, there is aseparation method by which stress is applied using wind pressure of agas jetted from a nozzle, ultrasonic waves, or the like.

The substrate 11 separated from the element layer 14 is preferablyreused to reduce cost. Further, the insulating film 15 is formed toprevent the element layer 14 from being scattered after removing theseparation layer 12. Since the element layer 14 is small, thin, andlightweight, after removing the separation layer 12, the element layeris easily scattered because the element layer is not firmly attached tothe substrate 11. However, by forming the insulating film 15 over theelement layer 14, the element layer 14 is weighted, making it possibleto prevent the element layer from scattering from the substrate 11.Further, although only the element layer 14 is thin and lightweight,when the insulating film 15 is formed thereover, the element layer 14can secure a certain degree of strength without having a shape that theelement layer 14 separated from the substrate 11 is rolled up due tostress and the like.

Next, one surface of the insulating film 15 is attached to a first sheetmaterial 775 and then the element layer is completely separated from thesubstrate 11 (FIG. 6A). In a case where part of the separation layer 12is left rather than removing the separation layer entirely, the elementlayer is separated from the substrate 11 by using a physical means.Subsequently, a second sheet material 776 is provided to the othersurface of the insulating film 15 opposite to the surface of theinsulating film 15 attached with the first sheet material 775, andthereafter, the second sheet material 776 is attached thereto byperforming one or both of heat treatment and pressure treatment. At thesame time of or after providing the second sheet material 776, the firstsheet material 775 is separated and then a third sheet material 777 isprovided instead of the first sheet material. Then, by performing one orboth of heat treatment and pressure treatment, the third sheet material777 is attached to the insulating film 15. Consequently, a semiconductordevice in which the element layer 14 is sealed with the second sheetmaterial 776 and the third sheet material 777 can be completed (FIG.6B).

Note that the element layer 14 may be sealed with the first sheetmaterial 775 and the second sheet material 776. However, in a case wherea sheet material used for separating the element layer 14 from thesubstrate 11 is different from sheet materials used for sealing theelement layer 14, the second sheet material 776 and the third sheetmaterial 777, which are made from the same material, may be used to sealthe element layer 14 as described above. This is effective in a case ofutilizing a sheet material with weak adhesion, and for example, in acase where there is a probability that the first sheet material 775 isalso attached to the substrate 11 in addition to the element layer 14when separating the element layer 14 from the substrate 11.

As each of the first sheet material 775, the second sheet material 776,and the third sheet material 777, a film made from polypropylene,polyester, vinyl, polyvinyl fluoride, or vinyl chloride, a paper madefrom a fibrous material; a stacked film of a base material film (such aspolyester, polyamide, an inorganic evaporation film, or paper) and anadhesive synthetic resin film (such as an acrylic synthetic resin or anepoxy synthetic resin); or the like can be used. Further, when a film isattached to the element layer by performing both of heat treatment andpressure treatment, an adhesive layer provided on a top surface of thefilm or a layer (which is not an adhesive layer) provided in anoutermost part of the film is melted by the heat treatment, and thenattached by the pressure treatment. Furthermore, adhesive layers may beor are not required to be provided over surfaces of the second sheetmaterial 776 and the third sheet material 777. The adhesive layerscorrespond to layers each containing an adhesive agent such as a heatcuring resin, an ultraviolet curing resin, an epoxy resin adhesiveagent, or a resin additive agent. In order to prevent intrusion ofmoisture and the like into an interior portion after sealing, sheetmaterials used for seaing the element layer are preferably subjected tosilica coating. For example, sheet materials in each of which anadhesive layer, a film made from polyester or the like, and a silicacoat are stacked, can be used.

Through the above described steps, a flexible semiconductor device canbe manufactured. By using the method described in this embodiment mode,a width between lines of the antenna of the conductive film (antenna)can be narrowed as 20±5 μm while maintaining a short processing timerequired for forming the antenna, and therefore, a region per unit areawhere the antenna can be formed can be increased. Accordingly, asemiconductor device including the antenna has an improved communicationdistance along with high reliability.

Embodiment Mode 2

In this embodiment mode, a method for manufacturing a semiconductordevice, which is different from the method described in Embodiment Mode1, will be described with reference to the drawings.

Although a case of forming the antenna in the interior portion of theelement layer along with the thin film transistors, is described inEmbodiment Mode 1, a method for forming a semiconductor device where anantenna is separately formed from thin film transistors and then theantenna and the thin film transistors are electrically connected to eachother, will be described in this embodiment mode.

First, a substrate over which an antenna is provided, is previouslyformed. A method for forming the substrate over which the antenna isprovided, will be described below.

A conductive film is formed over a substrate 235 by coating.Alternatively, in order to prevent part of a substrate 235 from beingetched in patterning the conductive film by laser irradiation in asubsequent step, a conductive film may be formed over the insulatingfilm by coating after forming the insulating film over the substrate235. Note that a glass substrate, a quartz substrate, a ceramicsubstrate, a metal substrate containing stainless steel, a siliconsubstrate, a semiconductor substrate having a surface formed with aninsulating film, a plastic substrate typified by an acrylic substrate,or the like can be used as the substrate 235.

The conductive film can be formed by using a fluid containing conductiveparticles and employing any one of methods of screen printing, spincoating, dipping, and a droplet discharging method using an ink-jettechnique or the like. Further, the conductive film may be formed usingCVD, sputtering, plating, or evaporation. In this case, the conductivefilm can be made from any one of Au, Ag, Cu, Ni, Pt, Pd, Ir, Rh, W, Al,Ta, Mo, Cd, Zn, Fe, Ti, Zr, and Ba, or an alloy or a compound thereof.Further, the conductive film can also be formed using polycrystalline Sior polycrystalline Ge doped with an impurity element such as phosphorus.In this embodiment mode, the conductive film is formed by screenprinting. Note that any conditions of screen printing, any conductiveparticles, and the like described in Embodiment Mode 1 may be used.

Next, the fluid containing the conductive particles applied over thesubstrate is baked and cured to form a conductive film 236 (FIG. 7A).Subsequently, the conductive film is subjected to patterning (scribing)by irradiation of a laser beam to form a wiring 237 (FIG. 7B). Thewiring 237 serves as an antenna.

A width between lines of the wiring (antenna) 237 formed by this methodis as narrow as 20±5 μm, and therefore, a region per unit area in whichthe antenna can be formed, can be increased. As a consequence,resistance of the antenna can be reduced, thereby improving acommunication distance of a wireless chip. Moreover, a processing timerequired for forming the antenna can be extremely shortened as comparedwith a case of employing a patterning method using a mask made from aresist.

As described above, a substrate over which the antenna is provided, iscompleted.

Next, a method for forming a substrate over which an element layer isformed, will be described. First, as described in Embodiment Mode 1 withreference to FIGS. 1A to 1C and FIGS. 2A to 2C, the conductive films 752to 761 are formed over the substrate 11 (FIG. 2C). Subsequently, aninsulating film 262 is formed over the conductive films 752 to 761 andthe insulating film 751 (FIG. 8A). The insulating film 262 is formed tohave a single layer or a stacked layer by using an inorganic material oran organic material by SOG, a droplet discharging method, or the like.In this embodiment mode, the insulating film 262 is formed with athickness of 0.75 to 3 μm.

Next, the insulating film 262 is etched by photolithography to formcontact holes through which the conductive film 752 and the conductivefilm 761 are exposed. Subsequently, a conductive film is formed over atop surface of the insulating film 762 to fill the contact holes. Thisconductive film may be formed using a material which can also be usedfor forming the conductive films 752 to 761 described in Embodiment Mode1.

Next, the conductive film is subjected to patterning to form a wiring281 being connected to the conductive film 752 and a wiring 282 beingconnected to the conductive film 761.

As described above, the substrate over which the element layer isformed, is completed. Although the substrate over which the antenna isprovided is first formed in this embodiment mode, the order of formingthe substrate over which the antenna is provided and the substrate overwhich the element layer is provided may be arbitrarily changed.

Afterwards, the substrate over which the element layer is provided andthe substrate over which the antenna is provided are attached to eachother (FIG. 8B). In this embodiment mode, as a means for attaching thesesubstrates, an anisotropic conductor 239 in which electric conductors238 are dispersed is used. The anisotropic conductor 239 can be pressedand made electric connection by the thicknesses of the wiring 281(wiring 282) and the antenna 234 at a region where the wiring 281(wiring 282) and the antenna 234 are provided. In the other region,since the electric conductors 238 keep a sufficient gap, thesesubstrates are not electrically connected to each other in a regionother than the region where the electric connection is made. Note thatin addition to the method by which the substrates are attached to eachother by using the anisotropic conductor, a method by which metal andmetal are attached to each other by ultrasonic waves (also referred toas “ultrasonic wave junction”) or an attaching method using anultraviolet curing resin or a two-sided tape can be used.

As described above, a substrate (hereinafter, referred to as an attachedsubstrate 240) in which the substrate over which the element layer isprovided and the substrate over which the antenna is provided areattached to each other is completed.

Next, the insulating film is etched to expose the separation layer 12 toform opening portions 273 and 274 (FIG. 9A). The opening portions 273and 274 are provided in a region where the thin film transistors and thelike included in the element layer 14 are not provided, or end portionsof the substrate 11. Further, the openings portions 273 and 274 can beformed by photolithography, laser irradiation, or grinding and cuttingan end surface of a sample.

Next, an etching agent is introduced to the opening portions 273 and 274to remove the separation layer 12 (FIG. 9B), if required. As the etchingagent, a gas or a liquid containing halogen fluoride is used. As a gascontaining halogen fluoride, for example, chlorine trifluoride (ClF₃)gas can be used. When the etching agent is introduced to the openingportions 273 and 274, the element layer 14 is separated from thesubstrate 11. Further, the separation layer 12 may be partly left ratherthan being removed entirely. By leaving part of the separation layer 12,consumption of the etching agent can be suppressed and a processing timerequired for removing the separation layer can be shortened, therebyreducing cost and realizing high efficiency. In addition, even afterremoving the separation layer 12, the element layer 14 can be kept overthe substrate 11 by part of the remaining separation layer 12.

The substrate 11 separated from the element layer 14 is preferablyreused to reduce cost. Further, the insulating film 15 is formed toprevent the element layer 14 from being scattered after removing theseparation layer 12. Since the element layer 14 is small, thin, andlightweight, after removing the separation layer 12, the element layeris not firmly attached to the substrate 11 so that it is easilyscattered. However, by forming the insulating film 15 over the elementlayer 14, the element layer 14 is weighted, making it possible toprevent the element layer 14 from scattering from the substrate 11.Further, although only the element layer 14 is thin and lightweight,when the insulating film 15 is formed thereover, the element layer 14can secure a certain degree of strength without having a shape that theelement layer 14 separated from the substrate 11 is rolled up due tostress and the like.

Next, the substrate 235 having the element layer 14 is completelyseparated from the substrate 11 (FIG. 10A). When part of the separationlayer 12 is remained over the substrate 235, the element layer 14 iscompletely separated from the substrate 11 by using a physical means.

Then, the substrate 235 having the element layer 14, which is separatedfrom the substrate 11, is sealed with a first sheet material 276 and asecond sheet material 277 (FIG. 10B). Note that, prior to sealing theelement layer 14, a protection film may be provided to cover a surfaceof the substrate 235 for the antenna so as to protect the element layer.

The first sheet material 276 and the second sheet material 277 can beattached to the element layer 14 by performing one or both of heattreatment and pressure treatment. As each of the first sheet material276 and the second sheet material 277, a film made from polypropylene,polyester, vinyl, polyvinyl fluoride, or vinyl chloride, a paper madefrom a fibrous material; a stacked film of a base material film (such aspolyester, polyamide, an inorganic evaporation film, or paper) and anadhesive synthetic resin film (such as an acrylic synthetic resin or anepoxy synthetic resin); or the like can be used. Further, when a film isattached to the element layer by performing both of heat treatment andpressure treatment, an adhesive layer provided on a top surface of thefilm or a layer (which is not an adhesive layer) provided in anoutermost part of the film is melted by the heat treatment, and thenattached by the pressure treatment. Furthermore, adhesive layers may beor are not required to be provided over surfaces of the first sheetmaterial 276 and the second sheet material 277. The adhesive layerscorrespond to layers each containing an adhesive agent such as a heatcuring resin, an ultraviolet curing resin, an epoxy resin adhesiveagent, or a resin additive agent. In order to prevent intrusion ofmoisture and the like into an interior portion after sealing, sheetmaterials used for seaing the element layer are preferably subjected tosilica coating. For example, sheet materials in each of which anadhesive layer, a film made from polyester or the like, and a silicacoat are stacked, can be used.

Next, the substrate sealed with the first sheet material 276 and thesecond sheet material 277 is divided into plural chips. As a method fordividing the substrate into plural chips, for example, a laseroscillation apparatus is used as a heating means and the periphery ofeach chip is irradiated with a laser beam through the second sheetmaterial so that the substrate is divided into the plural chips.

Further, as a heating means other than a laser beam, a wire may be used.Specifically, by pressing a heated wire to the periphery of a portion,which will be each chip later, the periphery thereof may be melted andsealed, and then cut.

Through the above described steps, a flexible semiconductor device(chip) is completed. By using the method described in this embodimentmode, the conductive film (antenna) formed having narrow width betweenlines of the antenna as 20±5 μm while maintaining a short processingtime required for forming the antenna, and therefore, a region per unitarea where the antenna can be formed can be increased. Accordingly, asemiconductor device having the antenna has an improved communicationdistance along with high reliability.

This embodiment mode can be implemented by being freely combined withthe above embodiment mode. That is, the materials and forming methodsshown in the above embodiment mode can be freely combined in thisembodiment mode.

Embodiment Mode 3

In this embodiment mode, a method for manufacturing a semiconductordevice, which is different from the methods described in EmbodimentModes 1 and 2, will be described with reference to the drawings.Differing from Embodiment Modes 1 and 2, in each of which the substrate11 is removed in the subsequent step, the substrate 11 is ground andpolished instead of removing the substrate 11 to be used as part of thesemiconductor device.

First, a base film 13 is formed over a substrate 11. Subsequently, anelement layer 14 is formed over the base film 13. Differing fromEmbodiment Modes 1 and 2, the separation layer 12 is not provided overthe substrate 11 and the base film 13 is directly formed on thesubstrate 11 in this embodiment mode.

Note that an antenna may be formed inside of the element layer 14 asdescribed in Embodiment Mode 1. Alternatively, after forming the elementlayer 14, a thin film transistor provided in an element layer and asubstrate over which an antenna is provided may be electricallyconnected to each other, as described in Embodiment Mode 2. In thisembodiment mode, after forming the antenna inside of the element layer14, an insulating film (protection layer) 15 is provided over theelement layer 14.

Next, a film 41 is formed over the insulating film 15. The film 41 ismade from a vinyl chloride resin, a silicon resin, or the like and has aproperty of being expanded when it is pulled out. Therefore, the film 41is also referred to as an expand film. Preferably, the film 41 has astrong adhesive property in a normal state and when the film 41 isirradiated with light, the adhesive property is weakened. Specifically,it is preferable to use an UV tape whose adhesive property is weakenedwhen being irradiated with ultraviolet light.

Next, one surface of the substrate 11 opposite to the other surface ofthe substrate over which the element layer is provided is ground by agilding means (see FIG. 11A). Preferably, the surface of the substrate11 is ground until the substrate 11 has a thickness of 100 μm or less.In general, in this grinding step, the surface of the substrate 11 isground by rotating one or both of a stage to which the substrate isfixed and the grinding means 31. The grinding means 31 corresponds to agrinding stone, for example.

Next, the surface of the substrate 11, which is ground, is polished by apolishing means (see FIG. 11B). Preferably, the surface of the substrateills polished such that the substrate has a thickness of 2 to 50 μm, andmore preferably, 4 to 30 μm. In this polishing step, the surface of thesubstrate 11 is polished by rotating one or both of the stage to whichthe substrate 11 is fixed and the polishing means 32 in the similarmanner as the above described grinding step. The polishing means 32corresponds to a polishing pad, for example. Thereafter, to remove dustgenerated in the grinding and polishing steps, washing is performed ifrequired, though not shown in the drawings.

Then, the substrate 11, the base film 13, the element layer 14, and theinsulating film 15 are partly cut by a cutting means 33. In this case,they are cut along a boundary line between integrated circuits such thateach of a plurality of integrated circuits is independently dividedwithout cutting the film 41. Further, only the insulating film providedin the element layer 14 is cut without cutting elements provided in theelement layer 14. Through this cutting step, a plurality ofsemiconductor devices (chips) 19 in each of which the substrate 11 whosethickness is reduced, the base film 13, and the element layer 14 arestacked, is formed (see FIG. 11C). Note that the cutting means 33corresponds to a dicer, a laser, a wire saw, or the like. The substrate11 whose thickness is reduced to 2 to 50 μm (preferably, 4 to 30 μm) hasflexibility so that the semiconductor devices 19 thus completed havealso flexibility. Accordingly, the semiconductor devices 19 manufacturedin this embodiment mode can be easily attached to a material body havingcurvature.

This embodiment mode can be implemented by being freely combined withthe above embodiment modes. That is, the materials and forming methodsshown in Embodiment Modes 1 and 2 described above can be freely combinedin this embodiment mode.

Embodiment Mode 4

This embodiment mode will describe a method for manufacturing a thinfilm transistor having a structure, which is different from the thinfilm transistors of the element layer 14 described in Embodiment mode 1.

First, as described in Embodiment Mode 1, a separation layer 12, a basefilm 13, and an amorphous semiconductor film 704 are formed over asubstrate 11. Subsequently, after crystallizing the amorphoussemiconductor film 704, patterning is carried out to form crystallinesemiconductor films 706 to 710. Then, a gate insulating film 705 isformed to cover the crystalline semiconductor films 706 to 710. A firstconductive film 1505 a and a second conductive film 1506 a are stackedover the gate insulating film 705. Note that in this embodiment mode,only the crystalline semiconductor film 706 is shown and will bedescribed (FIG. 15A).

Each of the first conductive film 1505 a and the second conductive film1506 a can be formed by using high melting point metal such as tungsten(W), chromium (Cr), tantalum (Ta), tantalum nitride (TaN), or molybdenum(Mo), or an alloy or a compound mainly containing high melting pointmetal. In this embodiment mode, the first and second conductive filmsare formed using different materials from each other such thatdifference in etching rate will be generated in an etching stepperformed later. Specifically, a tantalum nitride film is formed with athickness of 30 to 50 nm as the first conductive film whereas a tungstenfilm is formed with a thickness of 300 to 600 nm as the secondconductive film.

Next, a diffraction grating pattern or a mask pattern formed using anexposure mask to which an auxiliary pattern made from a semipermeablefilm having a function of attenuating light intensity is placed, isformed over the second conductive film (FIG. 15A). Here, a method forforming a mask pattern 1507 a will be described with reference to FIGS.17A to 17D.

FIG. 17A is a top view enlarging part of the exposure mask. Further,FIG. 17B is a cross sectional view of part of the exposure maskcorresponding to FIG. 17A. In FIG. 17B, the exposure mask corresponds tothe substrate 11 over which a resist is applied.

The exposure mask has light shielding portions 1701 a and 1701 b madefrom a metal film such as chromium (Cr), tantalum (Ta), or CrNx, and asemipermeable film 1702 as an auxiliary pattern, over alight-transmitting base substance 1700. A width of the light shieldingportion 1701 a is set to be t1, a width of the light shielding portion1701 b is set to be t2, and a width of a portion 1702 where thesemipermeable film is provided is set to be S1. Note that a spacebetween the light shielding portion 1701 a and the light shieldingportion 1701 b can also be set to be S1.

In this embodiment mode, as the exposure mask, an exposure maskincluding the semipermeable film 1702 made from MoSi_(x)N_(y) (x and yare positive integers) and the light shielding portions 1701 a and 1701b made from chromium (Cr) over the light-transmitting base substance1700 is used. Further, a material for the semipermeable film 1702 may bearbitrarily selected with respect to each exposure wavelength. Forexample, when using an F₂ excimer laser, TaSi_(x)O_(y) (x and y arepositive integers) may be used. When using an ArF excimer laser,MoSi_(x)N_(y) or TaSi_(x)O_(y) may be used. Further, when using i-line(light with a wavelength of 365 nm), CrO_(x)N_(y) (x and y are positiveintegers) may be used. When using an ArF excimer laser, CrF_(x)O_(y) (xand y are positive integers) or MoSi_(x)O_(y) (x and y are positiveintegers) may be used.

When a resist film is exposed to light by using the exposure mask shownin FIGS. 17A and 17B, light is transmitted around the light shieldingportions and through the semipermeable film so that a non-exposed region1507 a and an exposed region 1520 are formed.

Subsequently, development is performed to remove the exposed region 1520so that a mask pattern 1507 a shown in FIG. 15A is obtained. Note thatafter the development, baking at a temperature of about 200° C. may beperformed to change a shape of the mask pattern 1507 a.

Further, as an example of other exposure mask, FIG. 17C shows a top viewof an exposure mask in which a diffraction grating pattern 1712 having aplurality of slits provided at an interval of exposure limit or less isprovided between the light shielding portions 1701 a and 1701 b. Forexample, an exposure mask in which t1 is set to be 6 μm; t2, 6 μm; andS1, 1 μm, is used. Similarly, the mask pattern 1507 a shown in FIG. 17Acan also be obtained even when using the exposure mask shown in FIG.17C.

Next, the first conductive film 1505 a and the second conductive film1506 a are patterned by using the mask pattern 1507 a.

First, as shown in FIG. 15B, the second conductive film 1506 a is etchedby dry etching. As etching gases, CF₄, SF₆, Cl₂, or O₂ is used. In orderto improve an etching rate, a dry etching apparatus using a high-densityplasma source such as ECR (electron cyclotron resonance) or ICP(inductively coupled plasma) is used. Further, in a processing shapebased on the mask pattern 1507 a, in order to process an end portion ora sidewall portion into a tapered shape, negative bias voltage isapplied to a substrate side. By the etching, the mask pattern 1507 amade from a resist is subjected to sputtering with ions accelerated byelectric field so that mask patterns 1507 b, which are separatelyplaced, are formed.

Next, the etching gases are changed to CF₄ and Cl₂, and then etching oftantalum nitride of the first conductive film 1505 a is performed. Bythe etching, a first conductive stacked pattern including the firstconductive film 1505 b and the second conductive film 1506 b is formed(FIG. 15C). An angle of a tapered portion at an end portion of thesecond conductive film 1506 b and a surface of the substrate 11 is setto be 10 to 30 degrees. This angle is mainly determined in accordancewith a thickness of the second conductive film 1506 b. In thisembodiment mode, a length of the tapered portion is set to be 0.2 to 1.5μm, and preferably, 0.5 to 1 μm.

Next, by using BCl₃, Cl₂, and O₂ as etching gases, the second conductivefilm 1506 b is selectively etched based on the mask pattern 1507 b toform a second conductive film 1506 c. The mask pattern 1507 b made froma resist is subjected to sputtering with ions accelerated by electricfield and the size of the mask pattern 1507 b is reduced to form a maskpattern 1507 c. Further, in this etching, bias voltage applied to asubstrate side is reduced so as to prevent the first conductive film1505 b from being etched. An end portion of the second conductive film1506 c is recessed to be inside of the first conductive film 1505 b andthen a length of Lov is determined by the amount of recess as describedlater. Note that Lov is a region where the crystalline semiconductorfilm 706 is overlapped with the first conductive film 1505 b, which isnot covered with the second conductive film 1506 c. A second conductivestacked pattern including the first conductive film 1505 b and thesecond conductive film 1506 c is formed in such a manner and becomes agate electrode at an intersection with the crystalline semiconductorfilm 706 (FIG. 15D). Accordingly, an interval between two channelformation regions can be set to be not more than 2 μm. According to thepresent invention, an area occupied by TFTs having a multi-gatestructure can be reduced and the TFTs can be integrated, therebyrealizing a high-definition light emitting device.

Next, an impurity element imparting one conductivity type is added tothe crystalline semiconductor film 706. In this case, an LDD region, asource region, and a drain region can be formed in a self-aligningmanner by using the second conductive stacked pattern.

FIG. 16A is a cross sectional view showing doping treatment for formingan LDD region overlapping with a gate electrode. An impurity elementimparting one conductivity type is added into the crystallinesemiconductor film 706 underlying the second conductive film 1506 c. Byadding the impurity element imparting one conductivity type, firstconcentration impurity regions 1508 a, 1508 b, and 1509 are formed. Inthis case, the impurity element imparting one conductivity type is addedinto the crystalline semiconductor film 706 by passing through part ofthe first conductive film 1505 b which is not overlapped with the secondconductive film 1506 c. In this embodiment mode, phosphorus (or As) isused as the impurity element imparting one conductivity type to form anN-channel TFT. Accelerating voltage equal to or more than 50 kV isrequired to form the first concentration impurity regions 1508 a, 1508b, and 1509, though it is depending on a thickness of the gateinsulating film 705 or the first conductive film 1505 b. When the firstconcentration impurity regions 1508 a, 1508 b, and 1509 serve as LDDregions, an impurity concentration thereof may be adjusted to be 1×10¹⁶to 5×10¹⁸/cm³ (a peak value in an SIMS measurement).

When performing the doping treatment, the impurity element imparting oneconductivity type is not added into a region of the crystallinesemiconductor film 706 underlying the second conductive film 1506 c andthis region becomes a portion serving as a channel formation region of aTFT, which will be formed later. A plurality of regions which are notadded with the impurity element imparting one conductivity type isformed in the crystalline semiconductor film 706, and in this embodimentmode, two regions are formed. In this specification, an impurity regionsandwiched between the plurality of regions (channel formation regions),which is the two regions in this case, is referred to as an intermediateimpurity region.

FIG. 16B is a cross sectional view showing doping treatment for forminga source region and a drain region positioned outside of a gateelectrode. An impurity element imparting one conductivity type is addedinto the crystalline semiconductor film 706 while utilizing the secondconductive stacked pattern as a mask. By adding the impurity elementimparting one conductivity type, second concentration impurity regions1510 and 1511 are formed. The doping treatment for forming a sourceregion and a drain region is performed at accelerating voltage of 30 kVor less. An impurity concentration of the second concentration impurityregion 1510 may be adjusted to be 1×10¹⁹ to 5×10²¹/cm³ (a peak value inan SIMS measurement).

Note that the order of the doping treatment is not particularly limited.After performing the doping treatment for forming a source region and adrain region, the doping treatment for forming an LDD region may beperformed. Further, in this embodiment mode, doping treatments areperformed two times to form impurity regions having differentconcentrations; however, the impurity regions having differentconcentrations may be formed by doping treatment once by adjusting atreatment condition. Then, the insulating film 1512 and the insulatingfilm 1513 are formed over the TFT, contact holes connecting to secondconcentration impurity regions 1510 and 1511 are formed in theinsulating films 1512 and 1513, and conductive films 1514 and 1515 eachserving as a source wiring or a drain wiring are formed (FIG. 16C).

Through the above described steps, a thin film transistor in which aninterval between two channel formation regions is less than 2 μm, can becompleted. According to the present invention, an area occupied by TFTshaving a multi-gate structure can be reduced and the TFTs can beintegrated, thereby realizing a high-definition light emitting device.

This embodiment mode can be implemented by being freely combined withthe above embodiment modes. That is, the materials and forming methodsshown in Embodiment Modes 1 to 3 shown above can be freely combined inthis embodiment mode.

Embodiment Mode 5

In this embodiment mode, one embodiment mode of a case where asemiconductor device according to the present invention is used as anRFID tag, which is capable of transmitting and receiving data withoutcontact, will be explained with reference to FIGS. 12A to 12C.

An RFID tag 2020 has a function of communicating data without contact,which includes a power supply circuit 2011, a clock generating circuit2012, a data demodulation/modulation circuit 2013, a control circuit2014 for controlling another circuit, an interface circuit 2015, amemory 2016, a data bus 2017, and an antenna (antenna coil) 2018 (FIG.12A).

The power supply circuit 2011 serves to generate power sources suppliedfor respective circuits in a semiconductor device based on AC signalsinputted from the antenna 2018. The clock generating circuit 2012 servesto generate clock signals supplied for respective circuits in asemiconductor device based on AC signals inputted from the antenna 2018.The data demodulation/modulation circuit 2013 serves to demodulate andmodulate data for communicating with a reader/writer 2019. The controlcircuit 2014 serves to control the memory 2016. The antenna 2018 servesto transmit and receive radio waves. The reader/writer 2019 controls asemiconductor device, communication with the semiconductor device, andprocessing of data thereof. Note that the RFID tag is not limited tothis constitution and another element such as a limiter circuit of powersource voltage and hardware dedicated to crypt analysis may beadditionally provided, for example.

In addition, the RFID tag may be a type in which power source voltage issupplied to each circuit by radio waves without mounting a power source(a battery), a type in which power source voltage is supplied to eachcircuit by a power source (a battery) mounted instead of an antenna, ora type in which power source voltage is supplied by radio waves and apower source.

In the case of using a semiconductor device according to the presentinvention to an RFID tag or the like, it is advantageous in thatnon-contact communication is possible, multiple reading is possible,data writing is possible, transformation into various shapes ispossible, directivity is wide and a wide recognition range is provideddepending on the selected frequency, or the like. An RFID tag can beapplied to an IC tag which can identify individual information of aperson or an object by non-contact wireless radio communication, anadhesive label which can be attached to an object by label processing, awristband for an event or amusement, or the like. In addition, an RFIDtag may be processed with a resin material or may be directly fixed to ametal obstructing wireless radio communication. Further, an RFID tag canbe utilized for an operation of a system such as an entrance managementsystem and checkout system or an adjustment system.

Next, one mode of the practical use of the RFID tag using asemiconductor device according to the present invention will beexplained below. A reader/writer 2030 is provided on a side of aportable terminal including a display portion 2031, and an RFID tag 2033is provided on a side of merchandise 2032 (FIG. 12B). When thereader/writer 2030 is held up against the RFID tag 2033 of themerchandise 2032, information relating to merchandise, such as a rawmaterial and a place of origin of the merchandise, a test result perproduction process, a record of distribution process, and furtherdescription of the merchandise is displayed in the display portion 2031.In addition, merchandise 2036 can be inspected by using a reader/writer2034 and an RFID tag 2035 provided in the merchandise 2036, when themerchandise 2036 is transported by a belt conveyor (FIG. 12C). In thismanner, information can be easily obtained, and a high function and ahigh added value are realized by utilizing an RFID tag for a system.

This embodiment mode can be implemented by being freely combined withthe above embodiment modes.

Embodiment Mode 6

A semiconductor device according to the present invention can be appliedin a wide field. For example, the present invention can be applied to anelectronic device. The electronic device includes a television receiver,a computer, a portable information terminal such as a mobile phone, acamera such as a digital camera and a video camera, a navigation system,a projector, or the like. A case where a semiconductor device accordingto the present invention is applied to the mobile phone will beexplained with reference to FIG. 13.

The mobile phone includes casings 2700 and 2706, a panel 2701, a housing2702, a printed wiring board 2703, operating buttons 2704, and a battery2705. The housing 2702 incorporating the panel 2701 so as to be freelydetachable is set to the printed wiring board 2703. The form and size ofthe housing 2702 are appropriately changed in accordance with anelectronic device incorporating the panel 2701. A plurality of packagedsemiconductor devices are mounted onto the printed wiring board 2703,and a semiconductor device according to the present invention can beused as one of the semiconductor devices. Each of the plurality ofsemiconductor devices mounted onto the printed wiring board 2703 has anyone of function of a controller, a central processing unit (CPU), amemory, a power supply circuit, an audio processing circuit, atransmitting/receiving circuit, and the like.

The panel 2701 is connected to the printed wiring board 2703 via aconnecting film 2708. The panel 2701, the housing 2702, and the printedwiring board 2703 described above are contained inside the casings 2700and 2706 together with the operating buttons 2704 and the battery 2705.A pixel region 2709 included in the panel 2701 is disposed so as to beseen from a window provided in the casing 2700.

A semiconductor device according to the present invention is compact,thin, and lightweight. Accordingly, the semiconductor device can utilizelimited space inside the casings 2700 and 2706 of the electronic deviceeffectively.

Moreover, a semiconductor device according to the present invention canalso be used as an RFID tag, for example, in paper money, coins,valuable securities, certificates, bearer bonds, packing containers,books, recording media, personal items, vehicles, food items, clothes,healthcare items, living wares, medicals, electronic devices, or thelike. Specific examples thereof will be explained with reference toFIGS. 14A to 14H.

The paper money and the coins indicate currency in the market, whichinclude a note (a cash voucher) that is a currency in a specific area,memorial coins, and the like. The valuable securities indicate a check,a stock certificate, a promissory note, and the like (FIG. 14A). Thecertificates indicate a driver's license, a resident card, and the like(FIG. 14B). The bearer bonds indicate a stamp, a rice coupon, variousgift coupons, and the like (FIG. 14C). The packing containers indicate awrapping paper for a lunch box or the like, a plastic bottle, and thelike (FIG. 14D). The books indicate a book, a volume, and the like (FIG.14E). The recording media indicate DVD software, a video tape, and thelike (FIG. 14F). The vehicles indicate a wheeled vehicle such as abicycle, a vessel, and the like (FIG. 14G). The personal items indicatea bag, glasses, and the like (FIG. 14H). The food items indicategroceries, beverages, and the like. The clothes indicate wear, footwear,and the like. The healthcare items indicate a medical instrument, ahealth appliance, and the like. The living wares indicate furniture, alighting apparatus, and the like. The medicals indicate a medicine, anagrichemical, and the like. The electronic apparatuses indicate a liquidcrystal display device, an EL display device, a television apparatus (atelevision receiver and a thin television receiver), a mobile phone, andthe like.

By providing an RFID tag 20 for paper money, coins, valuable securities,certificates, bearer bonds, and the like, counterfeiting thereof can beprevented. In particular, by providing a wireless chip, which is forrecording a previous disease or a history of taking medicine, to ahealth insurance card, which is a kind of certificate, and checking thehealth insurance card when a doctor diagnoses, even in a case of goingto a plurality of hospitals, it is prevented to make a wrong diagnosison the kind of medicines, a dose amount, or the like. In addition, byproviding an RFID tag 20 for packing containers, books, recording media,personal items, food items, living wares, electronic devices, and thelike, the efficiency of the inspection system, the rental system, or thelike can be improved. By providing an RFID tag 20 for vehicles,healthcare items, medicals, and the like, counterfeiting and theftthereof can be prevented and the medicines can be prevented from beingtaken by mistake. The RFID tag 20 may be attached to a surface of anobject or embedded in an object. For example, the RFID tag 20 may beembedded in paper of a book, or embedded in an organic resin of apackage.

In this manner, by providing an RFID tag for packing containers,recording media, personal items, food items, clothes, living wares,electronic devices, or the like, efficiency of the inspection system,the rental system, or the like can be improved. By providing an RFID tag20 for vehicles, counterfeiting or theft thereof can be prevented. Inaddition, by embedding an RFID tag 20 in a creature such as an animal,each creature can be easily identified, for example, by embedding anRFID 20 in a creature such as a domestic animal, the first year of life,sex, breed, or the like thereof can be easily identified.

As described above, a semiconductor device according to the presentinvention can be used by being provided to any article. This embodimentmode can be implemented by being freely combined with the aboveembodiment modes.

The present application is based on Japanese Patent Application serialNo. 2005-158462 filed on May 31, 2005 in Japanese Patent Office, theentire contents of which are hereby incorporated by reference.

1. A method for manufacturing a semiconductor device, comprising:applying a fluid containing a conductive particle over a firstsubstrate; after forming a film containing the conductive particle bycuring the fluid containing the conductive particle, forming a wiringover the first substrate by irradiating the film with laser light;attaching the first substrate and a second substrate provided with aseparation layer and an element layer including a thin film transistorso that the wiring is electrically connected to the thin filmtransistor; selectively removing the attached first and secondsubstrates to form an opening portion; separating the second substrate;and sealing the first substrate provided with the element layer and thewiring by using a first flexible film and a second flexible film.
 2. Themethod for manufacturing a semiconductor device according to claim 1,wherein the wiring is formed by patterning the film containing theconductive particle by the laser irradiation.
 3. The method formanufacturing a semiconductor device according to claim 1, whereinscreen printing, spin coating, dipping or a droplet discharging methodis used as a method for applying the fluid containing the conductiveparticle.
 4. The method for manufacturing a semiconductor deviceaccording to claim 1, wherein a particle containing gold, silver,copper, an alloy of gold and silver, an alloy of gold and copper, analloy of silver and copper, an alloy of gold, silver, and copper, indiumtin oxide, conductive oxide in which 2 wt % or more and 20 wt % or lessof zinc oxide is mixed in indium oxide, conductive oxide in which 2 wt %or more and 20 wt % or less of silicon oxide is mixed in indium oxide, alead-free solder, or a solder containing lead, is used as the conductiveparticle.
 5. The method for manufacturing a semiconductor deviceaccording to claim 1, wherein the wiring is an antenna.
 6. A method formanufacturing a semiconductor device, comprising: applying a fluidcontaining a conductive particle over a first substrate; after forming afilm containing the conductive particle by curing the fluid containingthe conductive particle, forming a wiring over the first substrate byirradiating the film with laser light; attaching the first substrate anda second substrate provided with an element layer including a thin filmtransistor so that the wiring is electrically connected to the thin filmtransistor; after attaching, grinding the second substrate and polishingthe ground second substrate; and sealing the first substrate and thesecond substrate by using a first flexible film and a second flexiblefilm.
 7. The method for manufacturing a semiconductor device accordingto claim 6, wherein the wiring is formed by patterning the filmcontaining the conductive particle by the laser irradiation.
 8. Themethod for manufacturing a semiconductor device according to claim 6,wherein screen printing, spin coating, dipping or a droplet dischargingmethod is used as a method for applying the fluid containing theconductive particle.
 9. The method for manufacturing a semiconductordevice according to claim 6, wherein a particle containing gold, silver,copper, an alloy of gold and silver, an alloy of gold and copper, analloy of silver and copper, an alloy of gold, silver, and copper, indiumtin oxide, conductive oxide in which 2 wt % or more and 20 wt % or lessof zinc oxide is mixed in indium oxide, conductive oxide in which 2 wt %or more and 20 wt % or less of silicon oxide is mixed in indium oxide, alead-free solder, or a solder containing lead, is used as the conductiveparticle.
 10. The method for manufacturing a semiconductor deviceaccording to claim 6, wherein the wiring is an antenna.
 11. A method formanufacturing a semiconductor device, comprising: forming a conductivefilm over a first substrate; after forming the conductive film, forminga wiring over the first substrate by irradiating the conductive filmwith laser light; attaching the first substrate to a second substrateprovided with a separation layer and an element layer including a thinfilm transistor so that the wiring is electrically connected to the thinfilm transistor; selectively removing the attached first and secondsubstrates to form an opening portion; separating the second substrate;and sealing the first substrate provided with the element layer and thewiring by using a first flexible film and a second flexible film. 12.The method for manufacturing a semiconductor device according to claim11, wherein the wiring is formed by patterning the conductive film bythe laser irradiation.
 13. The method for manufacturing a semiconductordevice according to claim 11, wherein the conductive film is formed byCVD, sputtering, plating, or evaporation.
 14. The method formanufacturing a semiconductor device according to claim 11, wherein asolid laser having a wavelength of 1 nm or more and 380 nm or less isused in the laser irradiation.
 15. The method for manufacturing asemiconductor device according to claim 11, wherein the wiring is anantenna.
 16. A method for manufacturing a semiconductor device,comprising: forming a conductive film over a first substrate; afterforming the conductive film, forming a wiring over the first substrateby irradiating the conductive film with laser light; attaching the firstsubstrate to a second substrate provided with a separation layer and anelement including a thin film transistor so that the wiring iselectrically connected to the thin film transistor; grinding the secondsubstrate and polishing the ground second substrate; and sealing thefirst substrate and the second substrate by using a first flexible filmand a second flexible film.
 17. The method for manufacturing asemiconductor device according to claim 16, wherein the wiring is formedby patterning the conductive film by the laser irradiation.
 18. Themethod for manufacturing a semiconductor device according to claim 16,wherein the conductive film is formed by CVD, sputtering, plating, orevaporation.
 19. The method for manufacturing a semiconductor deviceaccording to claim 16, wherein a solid laser having a wavelength of 1 nmor more and 380 nm or less is used in the laser irradiation.
 20. Themethod for manufacturing a semiconductor device according to claim 16,wherein the wiring is an antenna.